Partner Support in Smokeless Tobacco Cessation Smokeless tobacco (ST) use continues to grow by at least 4% annually, and poses significant health risks. New methods are needed to expand the reach of ST cessation programs to ST users who do not seek treatment on their own. The goal of this proposal is to evaluate an innovative approach that encourages male ST users to quit by enlisting the support of their wives/ partners, both to lead the ST users to engage in treatment and to help them sustain abstinence. Our proposed intervention is based on responsiveness theory, which indicates that support will be received best if it conveys validation (respect for the ST user's decisions and autonomy), understanding (of the ST user's ambivalence about quitting and of the challenges of the cessation process), and caring (patience, warmth, and concern about the ST user's well-being). The intervention will present information via two modalities: a printed guidebook, and an interactive website presenting the guidebook information along with an interactive tailored support plan, videos modeling supportive behavior, and forums allowing participants to interact with each other and project staff. This multi- media approach is intended to appeal to women who may vary in learning styles, preferred mode of access to materials (i.e., in paper or on the web), and Internet access. In a previous feasibility study (R21-CA131461), we created an initial version of the guidebook and established that women can be readily recruited to an intervention to help their partners quit ST. We now propose to conduct a two-armed randomized clinical trial, comparing the intervention with a delayed treatment control giving access to the intervention website and printed guidebook after the final assessment. The primary outcome will be the ST user's 6-month cessation as reported at 7.5-month follow-up by the partner; secondary outcomes include ST users' quit attempts and change in the partner's supportive behaviors as a function of the intervention. We will test a mediating model relating change in partner's supportive behaviors to the ST user's cessation. The proposed study is innovative in two ways: (1) the target population - by recruiting the wives/partners of ST users, we will be encouraging cessation among ST users who are not themselves seeking treatment, including those at lower levels of readiness to quit, and (2) the theoretical basis for the intervention. If the proposed ais are achieved, we will have established a method that can expand the reach and effectiveness of existing ST cessation programs. The approach could be generalized to smoking cessation interventions and to other health behavior change interventions.